Vector and Pixel are actually 2 different things. Programs like Illustrator, Freehand and Corel Draw to name a few save there images in Encapsulated Postscript formats known as Vector Art. Each element is a mathematical equation that specifically maps out each shape, color and position. Vector images can be enlarged from a very small size to as large as a billboard without any loss of quality. Pixels on the other hand are the small dots that make up a photograph or picture in a psd, tiff, jpep or other image format. When you try to increase the size of this type of image, the quality decrease because the space between each pixel has to be interploted and gets very, very pixelized. You can actually see the blocks that make up the image. It is like the screen in a printed photograph in the newspaper that you look at with a magnifying glass. Hope this might help. - posted by Printtrax